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<table width="100%" summary="page for nassCDS"><tr><td>nassCDS</td><td style="text-align: right;">R Documentation</td></tr></table>

<h2>Airbag and other influences on accident fatalities</h2>

<h3>Description</h3>

<p>US data, for 1997-2002, from police-reported car crashes in
which there is a harmful event (people or property), and from which at
least one vehicle was towed. Data are restricted to front-seat
occupants, include only a subset of the variables recorded, and
are restricted in other ways also.</p>


<h3>Usage</h3>

<pre>nassCDS</pre>


<h3>Format</h3>

<p>A data frame with 26217 observations on the following 15 variables.
</p>

<dl>
<dt><code>dvcat</code></dt><dd><p>ordered factor with levels (estimated impact
speeds) <code>1-9km/h</code>, <code>10-24</code>, <code>25-39</code>, <code>40-54</code>,
<code>55+</code>
</p>
</dd>
<dt><code>weight</code></dt><dd><p>Observation weights, albeit of uncertain
accuracy, designed to account for varying sampling probabilities.</p>
</dd>
<dt><code>dead</code></dt><dd><p>factor with levels <code>alive</code> <code>dead</code></p>
</dd>
<dt><code>airbag</code></dt><dd><p>a factor with levels <code>none</code> <code>airbag</code></p>
</dd>
<dt><code>seatbelt</code></dt><dd><p>a factor with levels <code>none</code> <code>belted</code></p>
</dd>
<dt><code>frontal</code></dt><dd><p>a numeric vector; 0 = non-frontal, 1=frontal impact</p>
</dd>
<dt><code>sex</code></dt><dd><p>a factor with levels <code>f</code> <code>m</code></p>
</dd>
<dt><code>ageOFocc</code></dt><dd><p>age of occupant in years</p>
</dd>
<dt><code>yearacc</code></dt><dd><p>year of accident</p>
</dd>
<dt><code>yearVeh</code></dt><dd><p>Year of model of vehicle; a numeric vector</p>
</dd>
<dt><code>abcat</code></dt><dd><p>Did one or more (driver or passenger) airbag(s)
deploy? This factor has levels <code>deploy</code> <code>nodeploy</code>
<code>unavail</code></p>
</dd>
<dt><code>occRole</code></dt><dd><p>a factor with levels <code>driver</code> <code>pass</code></p>
</dd>
<dt><code>deploy</code></dt><dd><p>a numeric vector: 0 if an airbag was
unavailable or did not deploy; 1 if one or more bags deployed.</p>
</dd>
<dt><code>injSeverity</code></dt><dd><p>a numeric vector; 0:none, 1:possible injury,
2:no incapacity, 3:incapacity, 4:killed; 5:unknown, 6:prior death</p>
</dd>
<dt><code>caseid</code></dt><dd><p>character, created by pasting together the
populations sampling unit, the case number, and the vehicle
number.  Within each year, use this to uniquely identify the
vehicle.
</p>
</dd>
</dl>



<h3>Details</h3>

<p>Data collection used a multi-stage probabilistic sampling scheme.
The observation weight, called national inflation factor
(<code>national</code>) in the data from NASS, is the inverse
of an estimate of the selection probability.  These data
include a subset of the variables from the NASS dataset.  Variables
that are coded here as factors are coded as numeric values in that
dataset.
</p>


<h3>Source</h3>

<p><a href="http://www.stat.colostate.edu/~meyer/airbags.htm">http://www.stat.colostate.edu/~meyer/airbags.htm</a>\
<a href="ftp://ftp.nhtsa.dot.gov/nass/">ftp://ftp.nhtsa.dot.gov/nass/</a>
</p>
<p>See also\
<a href="http://www.maths.anu.edu.au/~johnm/datasets/airbags">http://www.maths.anu.edu.au/~johnm/datasets/airbags</a>
</p>


<h3>References</h3>

<p>Meyer, M.C. and Finney, T. (2005): <em>Who wants airbags?</em>. Chance
18:3-16.
</p>
<p>Farmer, C.H. 2006. <em>Another look at Meyer and Finney's &lsquo;Who wants
airbags?&rsquo;</em>. Chance 19:15-22.
</p>
<p>Meyer, M.C. 2006.  <em>Commentary on &quot;Another look at Meyer and
Finney's &lsquo;Who wants airbags?&rsquo;</em>. Chance 19:23-24.
</p>
<p>For analyses based on the alternative FARS (Fatal Accident Recording
System) data, and associated commentary, see:
</p>
<p>Cummings, P; McKnight, B, 2010. <em>Accounting for vehicle, crash, and
occupant characteristics in traffic crash studies.</em> Injury Prevention 16:
363-366. [The relatively definitive analyses in this paper use a matched
cohort design,
</p>
<p>Olson, CM; Cummings, P, Rivara, FP, 2006. <em>Association of first- and
second-generation air bags with front occupant death in car crashes: a
matched cohort study.</em> Am J Epidemiol 164:161-169. [The relatively
definitive analyses in this paper use a matched cohort design, using
data taken from the FARS (Fatal Accident Recording System) database.]
</p>
<p>Braver, ER; Shardell, M; Teoh, ER, 2010. <em>How have changes in air
bag designs affected frontal crash mortality?</em> Ann Epidemiol 20:499-510.
</p>
<p>The web page <a href="http://www-fars.nhtsa.dot.gov/Main/index.aspx">http://www-fars.nhtsa.dot.gov/Main/index.aspx</a> has a
menu-based interface into the FARS (Fatality Analysis Recording
System) data. The FARS database aims to include every accident in
which there was at least one fatality.
</p>


<h3>Examples</h3>

<pre>
data(nassCDS)
xtabs(weight ~ dead + airbag, data=nassCDS)
xtabs(weight ~ dead + airbag + seatbelt + dvcat, data=nassCDS)
tab &lt;- xtabs(weight ~ dead + abcat, data=nassCDS,
             subset=dvcat=="25-39"&amp;frontal==0)[, c(3,1,2)]
round(tab[2, ]/apply(tab,2,sum)*100,2)
</pre>


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